1. Field
Embodiments of the present invention relate to signal tracking. More particularly, various embodiments of the invention provide methods and apparatuses for estimating emitter geolocations utilizing data acquired from a plurality of collector elements.
2. Description of the Related Art
The ability to determine the source geolocation of emitted signals is becoming increasingly important as the use of wireless communications devices becomes commonplace throughout the world. For example, the U.S. Federal Communications Commission Enhanced 911 (E911) rules will eventually require cellular telephone carriers to identify the geolocations, i.e. the physical source locations, of subscribers who place calls to 911 or other emergency services. Additionally, wireless communication device users often desire to acquire accurate geolocations for navigation purposes, such as to generate a route between a current location and a destination. Further, military and law enforcement agencies often desire to locate sources of emitted signals for tracking and targeting purposes.
Methods and devices have been developed that enable signal emitter geolocations to be determined. Some of these methods include utilizing Global Position System (GPS) elements that must be coupled with signal emitters to determine geolocations, thereby increasing system cost and complexity. Other methods include utilizing one or more collector elements, such as antennas, to generate signal measurements and compute geolocations utilizing the generated signal measurements.
Although utilizing signal measurements enables geolocations to be determined without interfering with signal emitters, the algorithms that utilize signal measurements to determine geolocations often produce ambiguous or incorrect results.